WPFToolkit modified with different public key token

I had to modify the WPFToolkit.dll to add watermark for datepicker. after the modification, to use the dll in my project I had to provide a strong name to this dll thus overwriting the public key token of the dll to 5b20d1040a4ab839.

however the public key token of all the binaries supplied by microsoft has a public key token 31bf3856ad364e35

I also use Component one dll, which uses the old version of the dll with original public key token 31bf3856ad364e35 which will conflict with the new modified version of the dll with public key token 5b20d1040a4ab839

I can use the folowing probing solution only if the public key token of the Old version of dll and the modified version dll is same i.e(31bf3856ad364e35)